DefinitionThe duodenum is the first part of the small intestine. It is located between the stomach and the the middle part of the small intestine, or jejunum.After foods mix with stomach acid , they move into the duodenum, where they mix with bile from the gallbladder, and digestive juices from the pancreas.Absorption of vitamins, minerals, and other nutrients begins in the duodenum.ReferencesEvers BM. Small intestine. In: Townsend CM, Beauchamp RD, Evers BM, Mattox KL, eds. Sabiston Textbook of Surgery. 18th ed. Philadelphia, Pa: Saunders Elsevier; 2008:chap 48.